PIP: Data drom the Indonesian Contraceptive Prevalence Survey in 1987 was used to examine the extent to which socioeconomic factors affect the direct association between proximate determinants and fertility. The Bongaarts framework was applied to individual level data on married women who had at least on birth between 1982 and 1987. The fertility measure was the probability of having a birth in the last 12 months before the survey. Proximate determinants were breast feeding, fertile period (non-amenorrhea), sexual exposure, and contraceptive use. Socioeconomic variables were husband's education, wife's education, husband's occupation, religion, urban/rural status, and region of residence. The logit regression analysis is controlled by the age of the respondent and number of children ever born at the time of the survey. There is a possibility that socioeconomic variables may have a direct impact on fertility and the logit framework does not model perfectly the true stochastic model. Thus, a regression is specified in which the probability of experiencing a birth is regressed on both proximate determinants and socioeconomic determinants and on socioeconomic determinants alone. Results show that fertility is lower when the duration of breast feeding and level of contraceptive use is higher. Fertility is higher when the length of the fertile period and sexual exposure is higher. Education showed no significant impact on duration of breast feeding, but when both parents' education is considered, women's lack of education is related to having longer fertile periods (an average of 64 months). When the wife's education is considered alone, women with no schooling and less education have 56-44 more months of sexual exposure. The husband's education considered alone followed the same pattern. As level of parents' education rose, the probability of contraception increased. Women have shorter fertile periods when husbands are farmers. Religion explains duration of breast feeding and contraception. Urban/rural status explains variations in breast feeding duration and fertile period length. Women on Bali and Java were shown to have shorter fertile periods, less sexual exposure, and higher probability of contraceptive use. All 4 proximate determinants had an effect on fertility; most socioeconomic factors had no net effect on current fertility. Contraceptive use had the strongest effect on limiting fertility.